CVE-2026-34520

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Source
https://cve.org/CVERecord?id=CVE-2026-34520
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34520.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-34520
Aliases
Downstream
Related
Published
2026-04-01T20:27:48.350Z
Modified
2026-08-05T03:32:32.609576008Z
Severity
  • 2.7 (Low) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U CVSS Calculator
Summary
AIOHTTP: C parser (llhttp) accepts null bytes and control characters in response header values - header injection / security bypass
Details

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, the C parser (the default for most installs) accepted null bytes and control characters in response headers. This issue has been patched in version 3.13.4.

Database specific 
{
    "cwe_ids": [
        "CWE-113"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34520.json",
    "cna_assigner": "GitHub_M",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "fixed": "3.13.4"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}
References

Affected packages

Git / github.com/aio-libs/aiohttp

Affected ranges

Type
GIT
Repo
https://github.com/aio-libs/aiohttp
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
9370b9714a7a56003cacd31a9b4ae16eab109ba4
Fixed
9f7c7ab6f2924824e4a61a3b5c5c36475f4e25c6
Database specific 
{
    "source": "REFERENCES"
}

Affected versions

0.*
0.15.2
0.8.2
1.*
1.3.0
2.*
2.0.0
2.0.0rc1
4v0.*
4v0.21.6
v.*
v.0.6.5
v0.*
v0.1
v0.10.0
v0.10.1
v0.11.0
v0.12.0
v0.13.0
v0.13.1
v0.14.0
v0.14.1
v0.14.2
v0.14.3
v0.14.4
v0.15.0
v0.15.1
v0.15.2
v0.15.3
v0.16.0
v0.16.1
v0.16.2
v0.16.3
v0.17.0
v0.18.0
v0.19.0
v0.2
v0.20.0
v0.20.1
v0.21.0
v0.22.0
v0.22.0b0
v0.22.0b1
v0.22.0b2
v0.22.0b3
v0.22.0b4
v0.22.0b5
v0.22.0b6
v0.22.1
v0.3
v0.4
v0.4.1
v0.4.2
v0.5.0
v0.6.1
v0.6.2
v0.6.3
v0.6.4
v0.7.0
v0.7.1
v0.7.2
v0.7.3
v0.8.0
v0.8.1
v0.8.3
v0.8.4
v0.9.0
v0.9.1
v0.9.2
v1.*
v1.0.0
v1.0.1
v1.1.0
v1.1.1
v1.2.0
v2.*
v2.1.0
v2.2.0
v2.3.0
v2.3.0a1
v2.3.0a2
v2.3.0a3
v2.3.0a4
v3.*
v3.0.0b0
v3.0.0b1
v3.0.0b2
v3.0.0b3
v3.0.0b4
v3.1.0
v3.10.0
v3.10.0b0
v3.10.0b1
v3.10.0rc0
v3.11.0
v3.11.0b0
v3.11.0b1
v3.11.0b2
v3.11.0b3
v3.11.0b4
v3.11.0b5
v3.11.0rc0
v3.11.0rc1
v3.11.0rc2
v3.12.0
v3.12.0b0
v3.12.0b1
v3.12.0b2
v3.12.0b3
v3.12.0rc0
v3.12.0rc1
v3.13.0
v3.13.1
v3.13.2
v3.13.3
v3.2.0
v3.4.0
v3.4.0a0
v3.4.0a3
v3.4.0b1
v3.4.0b2
v3.5.0
v3.5.0a1
v3.5.0b1
v3.5.0b2
v3.5.0b3
v3.5.1
v3.5.2
v3.5.3
v3.5.4
v3.6.0
v3.6.0a0
v3.6.0a1
v3.6.0a10
v3.6.0a11
v3.6.0a12
v3.6.0a2
v3.6.0a3
v3.6.0a4
v3.6.0a5
v3.6.0a6
v3.6.0a7
v3.6.0a8
v3.6.0a9
v3.6.0b0
v3.6.1
v3.6.1b3
v3.6.1b4
v3.6.2
v3.6.2a1
v3.6.2a2
v3.7.0
v3.7.0b0
v3.7.0b1
v3.7.1
v3.8.0
v3.9.0
v3.9.0b0
v3.9.0b1
v3.9.0rc0

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34520.json"